反应详情

A solution of 4-nitrobenzyl 7-amino-3-chloro-3-cephem-4-carboxylate hydrochloride (15.0 g.), bis(trimethylsilyl)acetamide (11.3 g.) and trimethylsilylacetamide (9.7 g.) in tetrahydrofuran (300 ml.), a solution of diketene (3.41 ml.) in methylene chloride (4 ml.), a solution of bromine (2.27 ml.) in methylene chloride (4 ml.), a solution of sodium nitrite (3.1 g.) in water (20 ml.) and a solution of thiourea (4.0 g.) in water (40 ml.) were treated in a similar manner to that of Example 37-(1) to give 4-nitrobenzyl 7-[2-(2-aminothiazol-4-yl)2-hydroxyiminoacetamido]-3-chloro-3-cephem-4-carboxylate (syn isomer, 10.4 g.).